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“DIY Wall Insulation” Shows Many Things You Can Do Yourself to Make Your Walls More Air-Tight and Better Insulated. The Topics “Types of Siding Available” and “Insulated Siding” Give Information to Help Prepare You to Hire a Siding Contractor and Choose the Materials Which Will Best Increase the Insulation of Your Walls.

Topics

The Pros and Cons of Making Your Walls Air-Tight
How to Caulk Exterior Walls
Check for Missing Insulation in Your Walls
Blower Door Tests and Thermal Imaging Scans
DIY Wall Insulation by Adding Insulation
How to Seal Gaps Above Foundation Walls
How to Add Insulation to Basement Walls
How to Fill Empty Walls with Loose Fill Cellulose Insulation
Seal Leaks by Doing Repairs and Maintenance
Types of Siding Available
Insulated Siding


The Pros and Cons of Making Your Walls Air-Tight

Before sealing the leaks in your walls, consider the possible problems with having less air entering your home. Sealing the leaks could make the air quality worse and this could present problems for some persons living in your home.

The effects of making your home more air-tight are unpredictable. If there are smokers in your home or if you fry food often and you don’t have an exhaust fan above the stove, the air may become uncomfortable for some, but if many people live in your home and doors are being opened and closed all day, the air could not become stale. Allergy symptoms may become worse if you make your home more air-tight. If you use a fireplace and the fire burns poorly after you make your walls more air-tight, check if this caused the problem. You could partially open a door, if the fire begins to burn brightly it needs more oxygen. You could solve this problem by cutting a hole in the floor on each side of the fireplace and covering them with heating register grilles, which open and close.

There are advantages to sealing the gaps in addition to lowering your utility bills. Gaps on the outer surface of your house may be allowing rain water to enter and slowly damaging the walls. If rain water enters, mold can grow in the walls, which could make allergy symptoms worse. Gaps may have been letting insects enter. If air passes through the gaps, moisture may penetrate to places where it will not dry out easily, causing wood to rot, among other problems. Caulking large gaps could reduce a feeling of draftiness on very cold days.

How to Caulk Exterior Walls

In most home, DIY wall insulation is primarily caulking, sometimes for hours. Since all materials expand and contract with changing temperature and humidity, you should apply caulking wherever two pieces of wood, vinyl or any other material meet, to prevent a crack from forming.

Where to Apply Caulking Outside Your Home

diy wall insulation

Wood Siding Before Caulking

    • Apply caulking where ever unlike materials meet and where two surfaces meet at an angle, and where there is a crack in a wood or masonry wall that could let air leak through. Where unlike materials meet or two surfaces meet at an angle, one material may expand and contract more than the other when the temperature and humidity change. Caulking is designed to stick to both surfaces and expand and contract to keep the gap sealed.
    • Do not caulk the gap at the corner of the house if the joining walls are covered by aluminum, vinyl or steel siding. Caulking would prevent the siding from expanding in hot weather, possibly causing it to buckle.
    • diy wall insulation

      Caulking Around a Window Frame

      Caulk around the frames of the doorways and windows, except where the surrounding walls have aluminum, vinyl or steel siding. This siding must be allowed to expand and contract.

    • Caulk under the window sills.
    • Caulk around wall lamps and receptacles. This will seal air leaks and prevent moisture from causing rust damage. If a receptacle is embedded in the wall, remove the cover plate and caulk between the box and the wall. If the cover plate screw is rusty do not remove it because its head could break off. Instead, caulk around the cover plate with clear caulk.
    • Fill any gaps in the wall where a gas pipe, water pipe, electric cable or air conditioning tube enters the wall. If a gap is wider than about ¼”, use expanding foam sealant in place of caulk.
    • Caulk where phone lines, cables and piping enter the house.
    • Caulk around drier vents, bathroom exhaust vents and kitchen exhaust fans. Use clear caulk if the walls are masonry.
    • Caulk under door thresholds if there are gaps. Use clear caulk.
    • Caulk between the storm door frame and the house. Do this carefully using clear caulk for better appearance.
    • If a large pipe that was once used for heating oil enters the house through the basement wall and it is not capped, cap it or fill it with expanding foam sealant.
    • Caulk the bottom edge of wood siding, between the foundation and the siding. If the gap is greater than about ¼” use expanding foam sealant.
    • If your house has an overhang, i.e. one floor extends beyond the floor above it, caulk all around the bottom of the overhang. First, check if the wood panel beneath the overhang is firmly mounted and secure it with screws if it isn’t.
    • If you have a brick chimney next to a wall with wood siding, caulk the corners where they meet, using clear caulk. Water entering here would cause the siding to rot.
    • If your walls are brick, stone, block or stucco, check for cracks. Repair small cracks with masonry caulk. This is better than mortar because mortar cannot be forced into thin cracks. Also, mortar would be smeared on the wall and is hard to clean off. Even the smallest cracks should be repaired because water could enter them, freeze and expand, causing more damage. See Repair and Maintain Your Walls for Energy Savings
    • If you have a crawl space next to a basement, check the wall between them from the crawlspace side. Some holes and gaps may only be seen from that side. The holes should be filled even if the basement is unheated because much cold air will be drawn in though them in the heating season.
    • If the dryer vent passes through a rigid plastic window pane with a hole cut through it, check if the dryer hood has come loose from the pane. Attach it with polyurethane construction adhesive, and tape it to the pane with duct tape until the adhesive dries. If the hood is well-attached, check if there is a gap.


Where to Apply Caulking Inside Your Home

    • If your basement is unfinished and your foundation walls are exposed, caulk the holes where phone lines, cables and piping enter the house. If the holes are large use expanding foam sealant.
    • Caulk any gaps at the tops and bottoms of the baseboards on the exterior walls.
    • Check for gaps where the window and door frames (casings) meet the walls. Sealing these gaps could also prevent water vapor from entering the walls, possibly allowing mold to grow. Check the frames around the basement windows and doors also. If your basement walls are bare block or concrete, the gaps could be large. Fill gaps that are less than about ¼” wide with exterior caulk because the wall may get damp. Fill gaps that are wider than about ¼” with “expanding foam sealant for windows and doors”. This expands less than other types of expanding foam sealant, preventing the frame from bending. Air leaks will be the greatest through gaps in the basement door and window frames, when the central heating is on, due to the “chimney effect”.
    • Check for a gap where the dryer vent passes through the wall. If the wall is brick or block, there may be large gaps around the vent, and they should be filled with any type of expanding foam sealant. Fill small gaps with exterior caulk. If there are large gaps filled with fiberglass insulation, replace it with expanding foam sealant,  fiberglass insulation doesn’t stop air leakage.
    • If you have a fireplace, caulk where it meets the wall if there is a gap. Use siliconized acrylic caulk, in the color of your wall if it is available or use clear.
    • Check for gaps where a stairway runs along an exterior wall. The baseboard is normally notched to fit over the steps, and there may be gaps between the steps and baseboard.
    • If your basement walls are covered with paneling or drywall and your utility meters and electric panel and water shut off valves are behind the paneling or drywall, check if their access doors or access panels have weatherstripping. If there is no weatherstripping and no visible gaps, check for air leaks when the central heating is turned on. If there are gaps you would feel cold air leaking in. If air conditioning is operating, check for air leaking out of the house. Move an incense stick or candle along the access door or panel’s edges and watch the smoke. A candle is much less effective than an incense stick. You could also tape a thin plastic sheet over each door and panel. It will billow inward if air is leaking into the house or cling to the wall if air is leaking out. If air leaks through, seal around the door or panel with thin, compressible, self-adhesive foam weatherstrip tape. Staple it on at its ends using a heavy duty stapler and ¼” staples.

      how to insulate walls

      Fireplace Damper

    • If you have a fireplace that was covered over by drywall, check if air is entering your house through it by feeling the wall on a cold day. If it feels cold, much air is entering into the wall. The damper, which closes the chimney, is probably not closing tightly, allowing cold air in the chimney to fall down into the wall. If the wall feels cold, cut a large, square hole, using a wallboard saw, through the drywall to reach through to the damper.  Cut the hole carefully so that the piece you remove can be used to repair the hole. Check the damper for an air leak. Use spray foam insulation to fill gaps where air is leaking through. Have the hole repaired by a person experienced in plastering.
    • If your basement walls are exposed foundation block, check for air leaking through the foundation. Foundation blocks are hollow, and air can flow up and down inside a wall. If there is a spot where mortar is missing on the inside surface of the wall, air may enter the wall at a different place and flow to that spot and enter the house. You could check for leaks by moving an incense stick all over the walls, or by looking for missing mortar. The smoke from an incense stick can detect much smaller leaks than a candle. Some leaks are only detectable when the wind blows. Fill any leaks from between foundation blocks with masonry caulk or mortar.


How to Apply Caulking 

In this section, the term “caulking” is used to refer to both caulk and sealant. They are applied in the same way. The products designed for indoor use or for both indoor and outdoor use are normally caulk, and the products designed for outdoor use only are normally sealants.

    • When applying caulking from outside of the house, work on a day that meets the conditions given on the tube of caulking. Also, don’t apply it before 10:00 AM because the surfaces could be wet from dew.
    • If the caulking is cracked it is very old and has dried out. Try to remove and replace it all. Scrape it out with a sharp ½” wood chisel.
    • Prepare the surfaces that appear dirty. Metal, glass and plastic can be cleaned with mineral spirits or rubbing alcohol. Concrete, brick, block and stone can be cleaned with a wire brush. Bare wood can be cleaned in any of these ways. Remove debris from gaps with a paint brush.

      energy tips for walls

      5/8″ and 1/4″ foam backer rods

    • Fill gaps that are deeper than the maximum depth given in the directions (3/8” or ½”) with foam backer rod to reduce the gap before applying the caulking. Backer rods called, “poly foam caulk savers” are 5/8” diameter, and are sold in the weatherization departments of home centers and hardware stores. Many painting stores sell ¼” foam backer rods.
    • Fill wide, deep cavities in the wall inside the house with expanding foam sealant. This is costly to use for a single cavity in the wall because it dries up in the can a few hours after it is used.
    • If siding is loose at an end where you are applying caulk, first fasten it using spiraled siding nails. If the siding is asbestos or fiber cement (these are shingles designed to appear like asbestos shingles), pre-drill the nail holes with an 1/8” masonry bit to prevent cracking. If nailing it doesn’t attach it firmly, the sheathing behind it is probably slightly rotted there. Try nailing in two siding nails, one at a small angle to the left and one at a small angle to the right (toe nailed). If nailing it cannot attach it firmly, remove a large section of siding and replace the sheathing in that area. To remove the siding without damaging it, see How to Replace a Damaged Board of Lap Siding. If you don’t repair it in this way, use polyurethane construction adhesive in place of caulk. This may attach the shingles firmly.
    • If you are using acrylic caulk that is months old, soak it in warm water. If it was ever exposed to freezing temperatures it must be discarded. Don’t use caulk that is over one year old. If unsure how old the caulk is or if it was in freezing temperatures, test it. Apply a few inches of it to check how well it comes out of the tube. Then, wait for it to dry and check if it adheres well.

      Caulk Applied as a Wide Bead

      Caulk Applied as a Wide Bead

    • When caulking outside the house, push the caulking gun forward to force the caulk into the gap, and apply the caulk slowly. Make every bead of caulk as wide as possible so it can expand more as the two surfaces move relative to each other. Press each bead down with your finger so they adhere to the surfaces well.
    • When caulking inside the house, you may  choose to pull the gun for a neater appearance. Press the bead down with your finger to make an attractive concave surface and to make the caulking adhere better. Carefully remove the excess caulk
      with a putty knife.
    • Water-based (acrylic) caulk can be cleaned off with water, and oil-based (solvent-based) caulk can be cleaned off with mineral spirits or paint thinner. On all types, this is written on the tube.


Which Caulk or Sealant Should You Use?

The terms “caulk” and “sealant” are used interchangeably, but they are not the same. They are both normally applied the same way. Sealants are more elastic-they are made from materials that expand and contract more than caulk. The products formulated for indoor use or for both indoor and outdoor use are normally caulks, and the products formulated for outdoor use only are normally sealants.

There are so many types of caulk and sealant in a paint department or paint store that you could be overwhelmed. Some are for special conditions, such as high temperatures, fireproofing, or wet surfaces. Some only save you money. Cord caulking only has the advantage that it is easy to apply; it is not durable enough for general use. Latex and acrylic latex caulk are not durable enough if you are sealing cracks. They may need to be re-applied each time the house is painted.

If you are buying a caulk only to seal air leaks inside the house, use siliconized acrylic latex caulk (also called silicone acrylic) caulk. It is relatively durable, easy to apply, and paintable. It may be available at your store in white, clear and brown, and paint stores offer it in many colors.

If you are caulking outside the house, use a sealant. As explained above, sealants are more elastic. Outside, the wide changes in temperature will cause a gap between different materials to expand and contract, requiring a more elastic product. Silicone sealant is very durable and very elastic, but there are others also. Carefully read the label before buying a sealant. Silicone sealant, for example, cannot be applied at low temperatures, but there are brands of sealant that are formulated for use at low temperatures. Most brands of silicone are not paintable, but some are.

Some of the main advantages and disadvantages of several of the more durable types of caulk are given below. The largest selection can be found at home centers, but paint stores carry the best selection of colors. Butyl rubber sealant has basically been replaced by several sealants that are sold in roofing departments, such as “rubberized elastomeric cement” and “gutter and flashing sealant”.


Caulks and Sealants for Use Outside the Home, and Expanding Foam Sealant

Siliconized Acrylic Latex Caulk (Silicone Acrylic)

    • Easy to apply
    • Fairly good durability-10 to 20 years
    • Paintable
    • Adheres to almost all surfaces. At least one brand can be used on wood, glass, aluminum, masonry, brick, and metal.
    • Available in many colors
    • Less elastic than sealants
    • Most brands must be applied at above 40º
    • Moderate cost
    • Not permanently flexible

Silicone and Silicone Rubber Sealant

    • Very durable-products range from 10-year durability to 50-year durability
    • Permanently flexible
    • Can be used in areas of high temperature, such as lighting fixtures
    • Can be used in very damp areas
    • One brand of silicone rubber caulk can be applied in very cold weather but silicone caulk cannot be
    • Available in several colors
    • Most brands do not adhere to brick or concrete, but at least one brand is designed for metal, brick, concrete and granite
    • Cost is high

 Polyurethane Sealant

    • Excellent adhesion
    • Almost as durable as silicone
    • Permanently flexible
    • May deteriorate with long-term exposure to direct sunlight
    • Stretches and compresses well
    • Available in many colors.
    • Adheres to wood, glass, metal, masonry, stone, PVC
    • Apply at above 40º
    • Cost is high

Masonry Sealant

    • Best sealant for brick, concrete and stucco walls
    • Some brands must be applied at above 50º
    • Only available in the color of concrete.
    • Paintable

Expanding Foam Sealant

    • Fills gaps that are too wide for caulk
    • Expands to fill irregularly-shaped spaces
    • Lasts 10 or more years
    • Cans have “one time use”, so often, most is wasted
    • “Double-expanding” and “triple-expanding” brands can bend wood boards, such as door jambs


Caulks and Sealants for Use Inside the Home, and Expanding Foam Sealant 

Siliconized Acrylic Latex Caulk (Silicone Acrylic)

    • Easy to apply
    • Less expensive than most types of caulk
    • Fairly good durability-10 to 20 years
    • Paintable
    • Adheres to almost all surfaces. At least one brand can be used on wood, glass, aluminum, masonry, brick, and metal.
    • Available in many colors
    • Most brands must be applied at above 40º
    • Cost is moderate

Silicone and Silicone Rubber Sealant

    • Most durable of these types of caulk
    • Stretches and compresses better than other types (more flexible)
    • Permanently flexible, crack-proof, shrink-proof
    • Can be used in areas of high temperature, such as lighting fixtures
    • Can be used in very damp areas
    • Available in several colors
    • Most brands do not adhere to brick or concrete, but at least one brand is designed for metal brick, concrete and granite
    • High cost

Expanding Foam Sealant

    • Fills gaps that are too wide for caulk
    • Expands to fill irregularly-shaped spaces
    • Lasts 10 or more years
    • Cans have “one time use”, so often, most is wasted
    • Some brands recommended for use outdoors, except in warm climates
    • Some brands should be painted to protect from UV radiation
    •  “Double-expanding” and “triple-expanding” brands can bend wood boards, such as door jambs. Around windows and doors, use “window and door insulating sealant” expanding foam sealant.


Check for Missing Insulation in Your Walls


On a cold day, check for cold spots on the interior surfaces of your exterior walls. If your basement is “finished”, check the basement walls also. A cold spot could indicate that air is leaking into the walls from the outside or that some insulation is missing. Insulation could be missing near the top of a wall if it is loose fill insulation and it slid down. A cold spot next to a doorway or window could be due to a missing piece of insulation. The builder may have left it out because the space was too narrow for the batt insulation they were using in the walls.

One way to check for cold spots is to feel the walls, at least near the doors and windows and at the tops of walls. The most accurate way to check is to buy a non-contact infrared thermometer. These detect cold spots in winter and warm spots in summer. They are sold at home centers, starting at about $50. If you buy one, use it to check for missing roof insulation if your attic is finished, and check all over the basement walls for cold spots caused by infiltration.  In some homes, only the rooms that were added to the house have cold spots. In other homes, only the original rooms, which were built before fiberglass batt insulation was available have cold spots at the top, because loose fill insulation was blown into the walls and it has settled. If your house is very old, check along the bottom of the basement walls. The insulation may be missing due to water damage or rodents.

Cold spots close to windows and doors may be caused by air leaking into the walls where the frames meet the wall. If you have cold spots here, check if the caulking there is cracked or missing, and caulk if necessary.

If you find places where insulation is missing, you could fill the empty spaces with triple-expanding spray foam insulation. This is contained in liquid form in a pressurized can. It is sprayed into the walls through a ¼” tube, through ¼” holes drilled into the walls, and expands greatly to create hard foam. The triple-expanding type expands to the greatest volume. This is expensive so it may only be a good investment in very cold climates.

To apply spray foam insulation into the top of a wall, tap along the wall to find the approximate locations of the studs. They should be spaced at 16” intervals. Between every two studs, drill a ¼” hole and spray in the foam. After it has expanded, check if the cold area is completely warm or if more foam should be added. If the insulation is missing from floor to ceiling between two studs, drill a hole about a foot from the floor, spray in some insulation, let it fully expand, and then check how much area is still cold to find how many holes to make. There should be a board near the center (a fire stop). Locate it with a stud finder or by tapping the wall.

Blower Door Tests and Thermal Imaging Scans

Some companies that do complete home energy audits will instead do a “blower door test” together with a “thermal imaging scan”. These tests identify places in your exterior walls where energy is being wasted. In a blower door test, a large fan (blower) placed in the front doorway, blows air out of the house. The pressure in the house becomes lower, causing air to flow into the house more strongly through any leaks in the walls, so leaks can be more effectively detected. The energy auditor uses a smoke gun to detect leaks. You repair the leaks with caulk or spray foam insulation.

In a thermal imaging scan, also called an “infrared thermography inspection”, the energy auditor uses an infrared camera to take infrared pictures of your home from the inside and the outside. The pictures show different temperatures in different colors. The camera is photographing infrared radiation, which leaves the walls at a different frequency for each temperature. Where air is leaking out of the house the picture shows colors that indicate warm spots. A thermal imaging scan can also identify problems in your roof’s insulation and moisture problems which could damage your house. The picture above shows a yellow spot on the roof, where insulation is missing.

Thermal Imaging Scan

Thermal Imaging Scan

After Having an Infrared Imaging Scan:

    • If a scan taken from outside shows that much heat is escaping from between the first and second floors or from between the second and third floors, it is escaping at the band joists. These are 2”x 10” beams along the perimeter of each floor. If the heat detected is minor it may be heat that is conducted through the band joists. If it is significant, air is leaking out of the house from above or below the band joists. You can have these leaks repaired if you have lap siding such as clapboard, or vinyl or aluminum siding. An insulation contractor can remove a piece of siding at the band joist, drill ¼ “ holes through the band joist and shoot in foam insulation to fill the space behind it. Only contractors do this because shooting in the insulation requires training.
    • If a scan shows that small areas of a wall are missing insulation, you could fill the empty spaces with triple-expanding spray foam insulation. This is contained in liquid form in a pressurized can. It is sprayed into the walls through a ¼” tube, through ¼” holes drilled into the walls, and expands greatly to create hard foam. The triple-expanding type expands to the greatest volume. This is expensive so it may only be a good investment in very cold climates.

To apply spray foam insulation into the top of a wall, tap along the wall to find the approximate locations of the wall studs. They should be spaced at 16” intervals. Between every two studs, drill a ¼” hole where the wall is cold and spray in the foam. After it has expanded, check if the cold area is completely warm or if more foam should be added. If the insulation is missing from floor to ceiling between two studs, drill a hole about a foot from the floor, spray in some insulation, let it fully expand, and then check how much area is still cold to find how many holes to make. There should be a board near the center (a fire stop). Locate it with a stud finder or by tapping the wall.

    • If a scan of your basement ceiling shows that much air is entering the ceiling through the walls, there is probably a large gap between the foundation and the board that rests on it (the sill plate). To caulk this gap, see Seal the Leaks at the Top of the Basement Wall


How to Seal Gaps Above Foundation Walls


Your home’s basement walls or underground crawlspace walls are its foundation walls. A sill plate, which is normally a 2”x6” board, rests directly on the foundation walls all around the house. There are often gaps between the foundation walls and the sill plates because the top surface of the concrete or blocks is not smooth. On older homes, this gap was likely to have been caulked with oil based caulk that was designed to last for only 30 or 40 years, and then shrinks to allow large gaps. Also, where gaps are too wide for caulk the gaps may never have been sealed.

    • In place of a basement, your home may have an underground crawl space, or only one room may have a crawl space below it. These are about 3 ft. high and normally have bare earth at the bottom. There are normally two vents in the walls of each crawl space to allow air to flow in and out, to allow water vapor to escape. Do not caulk above these foundation walls because the moist air should escape.

      Pneumatic Stapler

      Pneumatic Stapler

    • If the top of a foundation wall is not accessible and you have a suspended ceiling (drop ceiling) remove a row of ceiling panels. If you have ceiling tiles, you could remove a row of them if you have the correct tool to re-mount them, but when remounted, their appearance will not be perfect. To remount them you must use 1” staples, which requires a pneumatic stapler or other type of power stapler. To remove the ceiling tiles, cut around their edges with a utility knife.
    • If you have a finished room in your basement that was originally a garage, it is likely that caulking was not applied at the top of the foundation wall, so it should be checked.
    • If your basement ceiling is drywall, it may be worthwhile to cut away a 16” strip of the ceiling along any wall where there are cold spots on the ceiling, to access the foundation wall. One way to check the ceiling for cold air is to cut a few 5”x5” holes and reach in to check for cold air. A 5”x5” hole can be patched with a 6”x6” wall patch, which is sold in painting departments. To repair theses holes requires experience in plastering, which you could hire a painter to do. Instead of making holes, you could check for large leaks by checking if the ceiling near the wall feels cold on a very cold day. Another way to check is to use a non-contact infrared thermometer. These detect cold spots in winter and warm spots in summer. They are sold at home centers, starting at about $50. To remove a strip of drywall:

      Spiral Saw

      Spiral Saw

      1. Snap a chalk line across the wall to mark the cutting line aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
      2. Use a sharp utility knife with the blade extended exactly ½”, the thickness of the drywall. DO NOT USE A WALLBOARD SAW because you could cut a power cable, phone line or other cable. Cables often lay on top of the ceiling. A faster and equally safe  way to cut a drywall ceiling is use an electric tool designed to cut drywall, such as a “spiral saw”. Set the cutting bit to the thickness of the drywall, 1/2” aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
      3. Apply sealant to the top and bottom surfaces of the band joists (rim joists). They are wooden beams that rest on edge on the sill plate along every wall. If there is fiberglass insulation against the band joists, remove it to caulk, fiberglass insulation does not stop air from leaking in. aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
      4. If your climate is very cold, staple insulation against the band joists before closing up the ceiling. This is commonly done in cold climates to increase the R-value of the band joists. Do not use insulation that could trap moisture, such as rigid foam, because moisture could cause the band joists to become damp, and possibly rot. Use un-faced, 3½” thick fiberglass batt insulation. If only faced insulation is available, tear off the paper facing. On the walls parallel to the floor joists, the joists may be double so insulation should not be needed. aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
      5. Replace the 16″ strip of drywall and plaster the seam. This must be done by someone experienced in plastering.

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DIY Wall Insulation by Adding Insulation
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A wall’s R-value is its ability to resist heat flowing through it due to reflection of heat radiation, and conduction through it. The R-value does not indicate how much energy is lost due to air leaking through the wall. R-values are given in ft2-deg-hr/Btu. It could be explained as the Btu’s that would pass through one square foot per hour, for each degree in temperature difference between the inside and outside of the wall.

“Dead air insulation” is any thin space between materials in which the air is trapped. It insulates better than a thick space because air will not move from the hotter side to the cooler side in a convection cycle. It insulates better if the space is closed on all sides to prevent air from entering or leaving. Any space has some insulation value because it blocks conduction, and because the two surfaces resist heat radiation. Double-glazed windows, for example, insulate well due to the thin space between two panes of glass.

Since the materials in a wall are thin, except the insulation that fills the wall, conduction through the materials adds very little insulation value. Most of the insulation value is due to the insulation that fills the walls, and to the surfaces of any material in the wall, because they reflect heat radiation. The surfaces of materials do not add insulation value if they contact another material.

The materials used to insulate walls have R-values printed on them, but when used in a wall, the wall’s R-value will be much less than the combined R-values of the materials in it. For example, a wall with no insulation may have an R-value of R-5, but a similar wall with R-11 fiberglass batt insulation may have an insulation value of R-13.

Do not insulate the crawl space walls. There is normally one vent on each crawl space wall to allow air to flow in and out, so the air temperature in the crawl space will be close to the outdoor air temperature regardless of the insulation in the walls. Also, the vents should be left open to prevent the water vapor that rises from the ground from damaging the floor joists. Instead of insulating the crawlspace walls, insulate its ceiling with fiberglass batt insulation. This is explained in the topic of home energy conservation, Interior Walls, Floors and Crawl Spaces.

Brick Veneer Walls

    • All modern brick homes have brick veneer walls. These have one layer of brick covering a framed wall. If your walls are brick veneer, do not insulate the gap behind the bricks. This drains away water from condensation due to warm air coming from inside of the house. The water also comes from moisture entering through the bricks.
    • If your air conditioning costs are much higher than your heating costs, you could paint your walls white to reflect the heat.

Solid Masonry Walls

    • If you have brick, block or stone walls and your home was built in the early twentieth century or earlier, your walls may not have wooden framing.  To check, remove a switch plate cover and look into the wall using a flashlight. If a wall is solid masonry, its interior surface may be plaster applied directly to the brick, block or stone, or there may be a layer of plaster with a space behind it. If there is space behind the plaster and the top of the walls are accessible from the attic, you can pour in vermiculate or perlite insulation balls, filling the space. If you have block walls you can pour the balls into the walls through the holes in the blocks. If your home is two or three stories, you can only insulate the top story with insulation balls for any of these types of walls.

Vermiculite has an R-value of about 2.1-R per inch of thickness and perlite is about 2.7-R (3½” fiberglass insulation is about R-3.3). However, they won’t increase the R-value of the wall by this much because the space they would fill is “dead air insulation”. See Dead air insulation Thus, it may not be cost effective to hire a contractor to do this work. Vermiculate and perlite insulation balls are not sold at most builder supplies stores or home centers, but are sold at stores specializing in insulation materials.

    • If your walls are brick with no frame, there may be a gap between two walls of brick. This insulates the house and prevents much of the moisture from seeping through the walls. The gap can be filled with liquid foam insulation by an insulation contractor. He will drill small holes between the bricks of the outer wall and shoot in insulation. The holes are only in the mortar so they can be patched with mortar and not be unattractive. This may be cost-effective if you live in a very cold climate. It is hard to estimate the increase in R-value that would be achieved because the gap that would be filled is dead air space insulation.
    • If your walls are solid masonry and your climate is very cold, you could install siding with insulation sheathing behind it. Your energy savings would not be enough to justify the cost, but if your walls are unattractive and you cover them with attractive siding, it would increase the property value of your home by improving its appearance and also by making it more energy efficient.

The most attractive types of siding may be wood lap siding, such as clapboard and shiplap, and fiber cement siding designed to appear identical to these types of siding, and vinyl siding that is designed to appear identical to these types of siding. The property value of your home would increase more by installing fiber cement siding than wood siding because wood siding requires painting and other maintenance. See Types of Siding Available and Insulation Sheathing: Panels and Fanfold Underlayment Some communities have guidelines and by-laws limiting the materials that can be used.

Frame Walls with No Insulation

    • To check if you have frame walls, use a stud finder and check that it indicates  studs, normally spaced at 16”, or knock on the wall to check for solid spots every 16”. To check if they have insulation, touch the walls on a cold day. If they feel cold they are un-insulated. To be certain, remove a switch plate cover and look in the wall using a flashlight.

      Foam Wall Plate Gaskets

      Foam Wall Plate Gaskets

    • If you have frame walls with no insulation and you will not fill them with insulation, they will be filled with cold air in the winter and hot air in the summer. This air leaks into or out of your living spaces at switches and electrical outlets. To seal these leaks, foam wall plate gaskets behind the switch plate covers and electrical outlet covers on the exterior walls. These are sold in the weatherization section of hardware stores and home centers.
    • If you have frame walls with no insulation, the best insulation to fill them with in most homes is loose fill cellulose insulation. In very cold climates, loose fill insulation, whether cellulose or another material, may not be suitable. This is explained below. Loose fill cellulose insulation is derived from newspaper and other wood product wastes and treated with fire retardant. Blowing in insulation is a do-it-yourself project and is the only way a do-it-yourselfer can insulate the walls. The only part of the project that some homeowners could not do is repairing the 3” diameter holes in the wall that they would cut to blow in the insulation, but you could hire a painter or handyman for this. You can rent a cellulose insulation blower from a home center or rental store and buy the insulation at a home center.

To put in loose fill cellulose insulation, cut one or two 3” diameter holes every 16” horizontally, stick the tube into each hole and blow in the cellulose. The tube will be at least 50 ft long, so you can leave the blower outside the house and run the tube to each wall through a window.” See the topic How to Fill Empty Walls with Loose Fill Cellulose Insulation. Watch a DIY video on insulating your walls with loose fill cellulose insulation.

Loose fill cellulose insulation has several problems. In very cold climates, filling the walls with any type of loose fill insulation could cause the walls to become damp inside from condensation because warm air escaping through the inner walls loses water vapor when it contacts the cold outer walls. This is because there is no way to insert a vapor barrier into the walls, as is done when walls are built. Spray foam insulation is recommended in very cold climates because air cannot pass through it. Condensation in the walls can also occur in very hot, humid climates because hot outside air passes through walls with loose fill cellulose insulation into air conditioned rooms. When it contacts the inner walls, condensation can form. Another problem with loose fill cellulose insulation is that some of the fire retardants used have been known to lose their effectiveness over time.

    • Another way to fill walls with insulation, which is far less popular, is with foam insulation. You must hire an insulation contractor to do this because the equipment cannot be rented. The contractor will drill one or two small holes every 16” and spray in the insulation in liquid form. It is expensive because spray foam is expensive, but it will give your walls a higher R-value and prevent dampness from condensation. It is probably only a good investment if you live in a very cold climate. The only other option is to use other types of loose fill insulation. They have lower R-values than cellulose and are not widely available.
    • Frame walls with wood siding and no insulation behind the siding (insulation sheathing) and no insulation in the walls typically have an R-value of about R-5 or R-6. If filled with loose fill cellulose insulation they are typically about R-11 or R-12, which is similar to walls with fiberglass batt insulation, which is in almost all homes built for many decades.

In 2004, the Oak Ridge National Laboratory (ORNL) published online the “Whole Wall R-Value Calculator”, to estimate the R-values of walls. Using this, R-values were calculated for wood frame walls made of 2×4 studs, with wood siding. The R-values were calculated with and without rigid foam insulation sheathing behind the wood siding, with loose fill and with sprayed-in polyurethane insulation. These are only rough estimates because there are many other factors that affect the R-value of a wall, so these R-values should not be used to estimate how many years it would take you to recover your investment in adding insulation to your walls. In fact, there is probably no accurate way to estimate this. As mentioned above, if your walls have no insulation, their R-value is probably about R-5 or R-6. The Whole Wall R-Value Calculator is given below:

Type of InsulationInsulation SheathingR-Value
Loose-fillnoneR-12
Loose-fill1" thickR-16
Sprayed-in polyurethanenoneR-17
Sprayed-in polyurethane1" thickR-21

    • If you insulate walls with loose fill cellulose you should paint the inside walls with vapor barrier paint because there will be no vapor barrier between the insulation and the inside walls. As explained above, without a vapor barrier, warm, humid air from inside the house will flow through the insulation and contact the cold outer walls (sheathing) and become cold, causing condensation and moisture in the walls. The problem is more serious in colder climates, and less serious if the sheathing is covered with a brand of housewrap that allows vapor to pass through it, such as TyvekTM. The problem is also less serious if there is rigid foam insulation sheathing behind siding because less air escapes through the walls. Some paint stores carry vapor barrier paint and at some you can order it. It is probably available only in white, but you can paint over it to change the color.
    • Hiring a contractor to install any type of insulation in the walls would probably take decades to pay for itself in energy savings, but it would significantly increase the market value of your home. Insulating your walls may make your home a little quieter, but the difference may not be noticeable if you have single pane windows and no storm windows. It also provides fire-proofing because it reduces airflow during a fire. Check with your insurance agent as to whether adding insulation would reduce your fire insurance premiums.Before buying insulation or hiring an insulation contractor, check with your local building authorities about the possibility of qualifying for a government grant or tax credit to help pay for insulation.


Unfinished Basement Walls


“Unfinished” basement walls have bare concrete or foundation blocks as their inside surfaces. The concrete or blocks are the foundation wall, and heat passes through it with little resistance. The R-value of a foundation block wall is only about R-1.5, which is not much greater than that of a single pane of glass. There are several ways to add insulation to the inside surface of basement walls. They are explainened in the topic, How to Add Insulation to Basement Walls An experienced do-it-yourselfer could do any of these methods, but may also need to watch DIY videos. Each of these ways reduces the moisture that enters through the walls from the ground into the basement. This reduces the humidity throughout the house and this could slightly reduce the home’s need for air conditioning.

If you use an insulation method that includes covering the wall with drywall or paneling, and you are an experienced do-it-yourselfer, you could build a suspended ceiling or tile ceiling with the help of a do-it-yourself book or website to create a valuable finished basement. If you do this you should hire an electrician to install wiring.

In very cold climates, the frost line may be below the level of the basement floor. In these climates, the basement walls should not be insulated because it could cause structural damage to the home’s foundation due to “frost heave”. If the frost line is below the level of the basement floor, as the ground freezes and thaws, moving up and down, it slides against the foundation. This could damage the foundation. If the basement walls are not insulated, the earth next to the foundation absorbs heat from the house so it doesn’t freeze, so frost heave is unlikely to occur. If you are unsure of whether the frost line is below your basement floor, contact your local HUD /FHA field office. Also, check your local building codes for approved insulation procedures

Paneled Basement Walls

To insulate paneled basement walls without destroying the paneling:

  1. If you have thin wood paneling, it can be removed without damage if it was nailed on with no adhesive. To check if adhesive was used in addition to the nails, hammer the nails through the paneling at several spots until the panels are free there using a nail set and hammer. If the panels aren’t glued on, there may be small areas were they are, and the panels will break there when you remove them, so you still cannot be completely sure. To be safe, don’t remove the panels unless you know if can buy panels of matching color, if necessary, to replace broken ones. To remove all of the panels, use a nail set to drive the nails through the panels.

    4 ft. by 25 ft. Roll of Double Reflective Insulation

    4 ft. by 25 ft. Roll of Double Reflective Insulation

  2. If you have thick wood paneling, it will be nailed on with finishing nails. Use a nail set to hammer the nail heads through the panels until the panels are free. There should not be any glue.
  3. After you remove the paneling, mount double reflective insulation or rigid foam insulation. The paneling may be nailed to ¾” thick furring strips, which are too thin to use rigid foam insulation. If it is nailed to 2”x 3” or 2”x 4” boards you can use either rigid foam insulation or sheets of double reflective insulation. Double reflective insulation is sold at home centers, and may be 5/16” thick. It has reflective surfaces on the front and back to reflect heat radiation (infrared radiation).

The reflective surface facing inside the house will only be effective if there is space between it and the paneling. You can create space by stapling it to the furring strips draped inward toward the foundation wall. This space will also be dead air space, which also increases the R-value. The R-value given by one manufacturer is R-3.7, but this depends on how much space is in front and back of it. The effectiveness of dead air space as insulation is greater if the space is larger, so the R-value of the double reflective insulation would be greatest if you drape it inward to the middle of the space

Double Reflective Insulation Stapled to Furring Strips, Draped Inward

Wood Siding in Poor Condition

    • If wood siding in poor condition is making your home unattractive, you could replace it and have rigid foam insulation sheathing panels mounted behind the new siding. In place of removing the old siding, you may be able to install new siding over the old siding if the new siding is thin. Thin siding could add much insulation value by trapping air behind it if the siding behind it is fairly air-tight.

Installing new siding over old siding would also save the high cost of removal and disposal of the old siding. In some cases, installing siding over old siding makes the home quieter to live in, but not if the windows are single-glazed and there are no storm windows. Installing new siding will not pay for itself by lowering your utility costs alone, but it may pay for itself if it improves the appearance of your home, and may make painting unnecessary. Some communities have guidelines and by-laws limiting the materials that can be used; for example, aluminum siding may not be permitted.

    • If your home has an historic character, there are arguments pro and con for installing siding. If the old siding is removed and replaced there may be irreversible damage to the historic building materials. It may result in the removal or covering of distinctive trim and other architectural details, or make them appear smaller and recessed into the rest of the building. Also, changing the features of an historic house may have an undesirable impact on the neighboring houses, especially if it is an historic district. An argument in favor of installing siding is that siding that matches the historic material in appearance is often available and could improve the appearance of the house.
    • If you have frame walls with no insulation, it is not very effective to install new siding with rigid foam insulation sheathing behind it because the insulation will not prevent cold air from entering the walls. This has been compared to wearing a sweater at 4” away from your body. You could replace the siding and blow cellulose insulation into the walls after removing the old siding and before installing the new siding. See How to Fill Empty Walls with Loose Fill Cellulose Insulation.
    • Removing and replacing your wood siding allows you to use very good insulation sheathing. The best is 1” thick rigid foam panels made of polyisocyanurate, with a reflective surface on one side to reflect heat. One manufacturer claims that it has an R-value of R-6.5, plus the R-value created by the reflective surface. Removing your siding to install a thinner, less expensive insulation sheathing may give you no better insulation than covering over the old siding if the old siding is clapboard. Clapboard has air spaces in front of it when covered by insulation sheathing.
    • It is better to remove and replace old wood siding than mount new siding over it if it has a significant amount of dry rot. It has dry rot if it feels soft and you can stick a nail through it by hand. If you only remove the rotted sections, the wood next to it is likely to have fungus and mold spores. The spores may not die; if their source of moisture is removed they become dormant, and if the wood later becomes moist the spores will cause the wood to rot. Rot can be a health hazard for persons in the home. Fungicides only temporarily kill active fungus.

If your siding has rotted areas and you would rather not remove it, try to find the source of the moisture such as gaps next to windows or a loose fascia board. If you cannot find it and correct it, it would be safer to remove the siding.

    • To choose a type of replacement siding and to choose the insulation sheathing, (or underlayment if you are mounting siding over old siding), see Insulation Sheathing: Panels and Fanfold Underlayment. This describes insulation sheathing and the insulating material that is mounted between old and new siding, fanfold underlayment, and helps you estimate how much you could lower your heating and cooling bills. See also Types of Siding.
    • If you are installing the new siding over the old, ask your contractor to use 3/8” rigid foam insulated “fanfold” underlayment insulation. Insulation contractors normally use ¼” or 3/8” fanfold rigid foam underlayment insulation, made of extruded polystyrene. These are available with and without a reflective surface, so request insulation with a reflective surface if either the old siding or the new siding has a space next to the insulation. Insulation sheathing and underlayment insulation are explained in Insulation Sheathing: Panels and Fanfold Underlayment

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Seal Leaks By Doing Repairs and Maintenance

If your home was built before the 1960’s, it is important to repair your siding, including brick siding, because the sheathing behind it is made of 1”x3’ or 1”x4” boards, and it may not be air-tight. Plywood sheathing became available In the 1960’s and home builders began using it in all homes. Sheathing built from boards was covered by tar paper or felt paper as a vapor barrier, but air can leak between the seams in the paper.

Repair Brick, Block and Stone Walls

    • If your walls are solid brick, block or stone, or the siding is brick or stone, check for cracks. Even very small cracks could allow water to enter, freeze and do damage. You could use binoculars to inspect the upper floors for small cracks. Also, check for cracks in the foundation. Cracks in the walls or the foundation are usually caused by very slight settling of the foundation. They are often above and below windows, where the walls are weakest. Even the smallest cracks should be repaired because water that enters in winter will freeze and expand, damaging the mortar and causing bricks to become loose. Caulk any cracks with masonry sealant.
    • There are warning signs that a wall may have small cracks that are hard to see: soft, crumbling mortar; loose bricks; and if the foundation is made of blocks, white stains on the inside of the foundation. Crumbling mortar and loose bricks are the result of water entering cracks and weakening the mortar. To check if a vertical crack is growing, which would be caused by a foundation problem, put a piece of tape over the crack and leave it on for months. If the tape becomes twisted the crack is growing. If a crack is less than ¼” wide, it is better to repair it with masonry sealant than mortar because sealant will expand if the crack becomes larger.

Mortar cannot be used without smearing a little on the bricks and it can only be cleaned off with muriatic acid.  This acid is dangerous for an inexperienced person to use, so you should hire a mason or experienced handyman to repair a large crack.

On walls that are not in direct sunlight, sealant should be applied at least two days after a rain because bricks dry slowly after a rain, especially in colder weather. If your home was built before the 1930’s, do not use the mortar that is sold in home centers and hardware stores to repair a brick or stone wall. This mortar contains Portland cement, which is as hard as concrete. It has been used to build walls since the 1930’s. Before then, masons used a mixture of lime and sand, which absorbed some moisture but allowed moisture to evaporate out. If your walls were built with this type of mortar and you repair them with modern mortar, the moisture will be trapped. When it freezes the bricks could be damaged or the new mortar could fall out.

    • If you have a vine-covered brick wall that is older than the 1930’s, it is possible that the roots of the vines have damaged the softer mortar that was used at that time. Remove some of the vines and inspect the mortar.

Repair Stucco Walls

    • If your walls are covered with stucco, cracks could allow air to leak into your house if the sheathing is made of boards. Homes built before the 1960’s, when plywood sheathing became available, had sheathing made from 3” or 4” wide boards. Check the walls for small cracks. If you find them, it would be safe to hire a home inspector or home engineer to check if the wall or foundation has a structural fault before repairing the siding. Repair even the smallest cracks with masonry sealant. If left un-repaired, water will enter and freeze, breaking off large pieces of stucco. Scrape out hairline cracks to make them wide enough to caulk.
    • If a small piece of stucco has broken off or if there is a large crack, repair it with stucco repair compound. This is sold pre-mixed, in small containers. With this, you cover the damaged area with a polyester membrane and coat the membrane with compound. After applying the patch, cover it with textured paint to disguise it.
    • If a large piece of stucco has fallen off, you can repair it yourself by watching a do-it-yourself video. The hard part is making the patch appear the same as the surrounding area. Make test patches on plywood until you can make them perfect. Stucco is not painted, colored pigment is mixed in to give it color. The color fades greatly as the stucco dries, so make test patches of several shades and let them dry. Make the repair when there will be no freezing temperature for a long time. The instructions may require that there be no freezing temperature for six weeks.
Masonry grout bag

Masonry grout bag

Repair Fieldstone Foundation Walls

    • If you have fieldstone foundation walls and air leaks in between the stones, plug the leaks with mortar. Use a masonry grout bag to force in the mortar. This is a canvass bag in the shape of a large funnel. They are sold at building supplies stores. Fill it 1/3 full of mortar, insert it in the crack and squeeze it to fill the crack.

Repair Unpainted Wood Siding

    • If your siding is a species of wood that does not require painting, such as cedar, cypress or redwood, or is pressure treated pine, protect it by staining it or applying a water repellent product. Coating it will protect it from rotting and warping, which could allow air to leak through if the sheathing is made of boards. It will also preserve its beauty. As mentioned above, if your home was built before the 1960’s you can assume the sheathing is made of boards.
    • There are many types of water repellent products and stains available in 5 gallon cans in paint stores. Wood stain is designed to be absorbed into the wood and water repellent products are designed to coat and waterproof the surface. Some products are designed for pressure treated wood. Stains are much more expensive and last much longer than water repellent products. Stains have 10, 15, or 25-year warranties. Their durability depends on the quality of the product and on whether the sun shines directly on the wall, and the temperature and dryness of the wall when the stain was applied. If you are applying wood stain yourself, ask at the paint store for advice. Instructions may be given on the manufacturer’s website. Before buying any product, read other manufacturers’ websites to compare their products and to help you to choose the best one for your wood and your climate.

Repair Aluminum, Vinyl, and Steel Siding

    • If your siding is made from horizontal strips of aluminum, vinyl, or steel and your home was built before the 1960’s when sheathing was made of boards, check for loose or buckled strips. Air that leaks through the siding may leak through the sheathing boards. As mentioned, the boards are covered by felt paper, but there may be gaps where sheets overlap.
    • If your siding has streaking or staining, water may be leaking in and running down the wall from behind the siding. Try to find the source of the water and repair the leak. The wooden sheathing behind it may be badly rotted from the water and need to be repaired. Also, the sheathing may have mold, which could affect the air quality inside your home.
    • If strips of siding buckle when the weather is hot, they were installed incorrectly. The expansion gaps at the ends of the pieces are not large enough to allow the pieces to expand in hot weather. Do not nail the buckled pieces onto the sheathing. Instead, trim off about ¼” from each end. Trim it without removing it by drilling a row of very small holes along each edge at ¼” from the end.

Repair Siding That is Not Aluminum, Vinyl, Steel, Masonry, Stucco or Fieldstone

The remaining types of siding are combined here because they can have cracks, which can be caulked, and other types of damage that can be repaired.

“Engineered wood” includes various materials that are manufactured by gluing together strands or particles of wood. Fiber cement is a mix of wood pulp and Portland cement. Asbestos siding is a mix of cement and strands of asbestos. Wood lap siding is any wood siding made from horizontal-mounted boards.

    • Seal cracks in real wood or engineered wood with clear silicone sealant for outdoor use. Silicone sealant has excellent elasticity.
    • Seal cracks in asbestos or fiber cement siding with masonry sealant. This adheres well because these materials are made of cement with particles mixed in.

      Ring shank siding nail

      Ring shank siding nail

    • Nail in any loose nails to prevent the shingles or boards from coming loose. Also check for loose nails in trim boards at windows, ends of walls, etc. If a nail goes in easily, the sheathing may be slightly rotted. Put in two nails near it, driven in at different angles for much greater strength. This is called “toe nailing”. Use ring shank siding nails.
    • If a wooden shingle or wood lap siding board is cracked, put glue or construction adhesive in the crack, close the crack and nail in a nail next to it to hold it closed until the adhesive dries.
    • Repair badly split pieces of wood siding with polyurethane construction adhesive. This fills small gaps and joins pieces very strongly. If the wood is slightly damp, use “subfloor and deck construction adhesive”. This sticks to slightly wet wood, and fills small gaps. If necessary, drill pilot holes and screw the siding to the sheathing while the adhesive dries, and remove the screws later.

      Asbestos Siding

      Asbestos Siding

    • Repair woodpecker holes. Carve a piece of wood to fit each hole and glue it in with construction adhesive. Construction adhesive fills small gaps, so the plug doesn’t have to fit tightly. If woodpeckers make more holes, there are insects in the wood that they are eating. If you know what type of insects they are you can spray the siding with the correct insecticide.
    • If you have asbestos siding, it is installed as shingles. These are made from cement filled with particles of asbestos. Check if any shingles have cracks or missing pieces. Seal cracks with masonry sealant.


Repair Small Rotted Areas In Wood Siding:

To repair a small rotted area in wood siding, first find the cause of the rot. Rot is fungus growing in the pores of the wood when the wood is wet, and wood will only rot if it gets wet often. It most often rots because the end of a board is unpainted or not well-caulked, allowing water to be absorbed through the pores of the wood, often where two boards meet end-to-end.

The wood is rotted if:

    • Paint is peeling off in one small area
    • The wood is spongy in one area
    • The wood breaks off in chunks rather than splinters


A. Repair Small Rotted Areas Using a Wood Patch

A wood patch is a piece of wood cut to replace the wood in the rotted area.

    1. Do the repair when the weather is warm enough and rain is not forecast, to meet the requirements of the paint.
    2. Cut out the rotted wood and some surrounding wood. The surrounding wood will have fungus in its pores. The easiest way to remove the piece may be to drill a line of 1/8” holes across it.
    3. Cut a piece of wood to fit into the space. A miter saw is the best tool to use. Cut the piece from a scrap piece of hardwood or durable softwood such as spruce or redwood if available. Don’t use pressure treated wood unless the rotted wood is pressure treated because they can’t be painted with the same paint.
    4. Paint the cut surfaces of the original board with a heavy coat of paint. Thoroughly paint cut surfaces of the patch piece. This is the only way to prevent rot. If the original board was painted with oil-base paint, paint the patch piece with oil-base paint, if it was painted with water-base paint use water-base paint. Do this because the final coat of paint will be applied to both the patch piece and the surrounding area, and paint only sticks well to similar paint.
    5. When the paint is very dry, glue in the patch piece with polyurethane construction adhesive. Dry the paint with a hair dryer if necessary. Polyurethane is stronger than the other common types of construction adhesive and it fills small gaps, keeping out the water. Use enough to fill the gaps so caulking is not needed. Drill a pilot hole in the patch piece and nail in a finishing nail to hold it in place while the adhesive dries.


B. Repair Small Rotted Areas Using Wood Filler

    1. Buy wood filler. Exterior epoxy wood filler is the most durable but some brands do not cure below 65º.
    2. Cut out the rotted area. If the rotted area is large, drill many 3/16” holes into the surface you have cut to allow the wood to dry out until the next day (cover it if rain is forecast). Before applying the epoxy, saturate the holes with wood hardener and allow it to dry. This is formulated to strengthen rotted wood. It is sold in paint departments.
    3. Fill the area with wood filler.
    4. Prime and paint the area if the temperature and rain forecast meet the requirements of the paint. If the surrounding wood is painted with oil-base paint, use oil-base paint and if it is water-base paint use water-base paint. To know which type it is, check if it rubs off with latex paint remover.


Repair Badly Warped Pieces of Wood Siding

    1. Drill pilot holes and nail the siding back into place with ring-shank siding nails.
    2. If the siding cannot be nailed into place because the sheathing behind it is rotted, it would be best to replace that sheathing. If it won’t be replaced, fill the space behind the loose shingle with construction adhesive using a caulking gun, to prevent the siding from warping further. You should be able to bend it close to the sheathing and keep it there until the adhesive dries by screwing it to the sheathing. Remove the screws after the adhesive dries if they are unattractive. If sheathing is wet, wait for it to dry or use “subfloor and deck construction adhesive”, which adheres to wet wood.


Replace Damaged Boards of Lap Siding

Clapboard siding

Clapboard siding

Shiplap Siding

Shiplap Siding

Lap siding is any wood siding made from horizontal-mounted boards. Shiplap siding has boards that overlap each other with the top of one board fitting into a notch in the bottom of the board above it. Clapboard siding has boards that overlap each other and are thinner on the top. These may be made from real wood, engineered wood or fiber cement. See Available Types of Siding.  Shiplap and clapboard are the most common types of wood lap siding.

Buy an identical piece of siding. Do not remove the damaged piece to find its size and shape because you may not find a similar piece. Check at builder supplies stores and lumber yards. You may be able to order it there if they don’t stock it. If the piece you need is very old and not available, it may be sold by architectural salvage companies.

  1. Slip a hacksaw blade under the piece above the damaged piece and cut those nails. Slip the blade under the damaged piece and cut those nails.
  2. Slip a pry bar under the damaged piece, pry it up and put shims behind it to separate it from the piece behind it. Use a small hand saw (e.g., a jab saw) or a jigsaw to cut out the damaged area. A drywall saw can be used if the blade is not dull from cutting drywall. If you cut the vapor barrier material behind the siding, seal it with roofing cement.
  3. Cut the replacement piece to fit very tightly. To make it fit perfectly, cut it slightly too long and sand it to size with a belt sander or rasp (wood file).
  4. Use a heavy coat of paint to coat the ends of the replacement piece and the cut ends of the original siding, to close the pores and prevent rot.
  5. Slide in the replacement piece. Nail it with ring-shank siding nails, drilling pilot holes so you don’t split the wood. Countersink the nail heads and fill with paintable exterior caulk.
  6. When the paint dries, caulk where the replacement piece meets the old siding. When the caulk is dry, paint the replacement piece.


Replace a Section of a Board of Board-and-Batten Siding

Board-and Batten Siding

Board-and-Batten Siding

Board-and-batten siding has wide vertical boards, with thin strips of wood called battens covering the seams where the boards join. It is made in a variety of tree species.

If a vertical board is badly rotted or broken and must be replaced:

  1. Remove the battens over the damaged board using a crowbar.
  2. Cut out the damaged section of board. Cut it with a circular saw, with the blade set ¾” deep to avoid cutting the vapor barrier behind it. If you cut the vapor barrier, repair it with roofing tar.
  3. Buy a replacement piece of a species of wood similar to what is on your house. If your siding is painted, it is almost certainly pine or fir and you can replace it premium grade pine. A 10” or 12” wide piece, if you need that, will probably not be available at your local home center in premium grade, but it is sold at lumber yards and building supplies stores. If it is unpainted redwood or cedar, this is only sold at lumber yards and building supplies stores.
  4. If the piece you buy is slightly wider than the piece you removed, cut the piece to a width that allows an 1/8” gap on each side for expansion. It will expand from heat and humidity in the summers. Cut its length to fit in tightly.
  5. Paint the ends of the replacement board heavily to close the pores and prevent rot. Also, paint the original board where it was cut.
  6. Nail the replacement board in place using 2½” ring-shank siding nails. Nail on the battens using the existing nail holes, with longer nails than you removed.


Replace Damaged Asbestos Shingles

There is no health hazard in removing an asbestos shingle if you wear gloves, but wash your hands after you remove it to be safe. Before removing it, find out what your local ordinance requires for the disposal of a single piece of asbestos shingle.

  1. Buy a matching shingle. Asbestos shingles are no longer sold, but fiber cement shingles that are designed to match asbestos shingles are sold in a large variety of shapes and sizes. They can be ordered at some home centers.
  2. Paint the new shingle and let it dry.
  3. Break the damaged shingle and remove it. This must be done because you cannot bend up the shingle above it to get access to the nails. Be careful not to damage the adjoining shingles. The shingle should be attached by two nails.
  4. Drill two nail holes into the new shingle using a masonry bit. Break away some of the new shingle that would interfere with the old nails and slide in the new shingle. Nail it in using two ring-shank siding nails.

    Wall Covered by Plywood Siding

    Wall Covered by Plywood Siding


Seal Gaps in Plywood Siding.

Plywood siding is mounted to the walls in 4’ by 8’ panels. It is sometimes mounted directly to the wall studs with no sheathing. The panels normally have vertical grooves about every 4” to give the appearance of vertical boards. Check for gaps at the seams where the panels meet. These are normally caused by a warped panel. If there is no sheathing, these gaps will allow air to leak directly into the walls. If there are gaps, close them by nailing the edges of the panels to the studs using ring-shank siding nails and caulk the seams with  clear silicone sealant caulk. Check all of the seams for missing or dried-out caulk, and re-caulk them if needed.
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How to Add Insulation to Your Basement Walls

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As explained above, do not insulate the basement walls if you live in a very cold climate. There is a risk that this could cause foundation damage due to “frost heave” if the frost line is as low as the basement floor. If you are unsure of whether your climate is this cold, contact your local HUD /FHA field office.

Before adding insulation to the inside surface of your basement walls, you could coat the walls with a masonry waterproofer such as DRYLOKTM. This product will prevent water from entering the house for up to 10 years, depending on the size of the holes or cracks. In addition to coating the walls you could leave a ½” gap below the insulation and drywall or paneling you install, to prevent any water that leaks in from becoming trapped.

Before insulating your basement walls, check for signs that water has leaked through. If water is entering your basement, the problem should be repaired before you insulate the walls so the material you mount does not become moldy or in other ways damaged. On a block wall, the water will leave a dark line where it ran to the floor. Also, check for air leaks on a cold day. If your basement walls are block there could be air leaks below ground level because air can flow down through the holes in the blocks. Seal the holes where water or air enters using masonry caulk. If water is leaking through, try to fix the problem in one of these ways:

    • Repair the rain gutters or downspouts.
    • Clean the gutters
    • If water puddles next to the house, add soil near the walls to improve the drainage away from the house.
    • If your yard has a large slope that causes rain water to drain toward your house, hire a contractor to build a “landscape berm”. This is a long mound of earth covered with grass, located to direct drainage away from your house.
    • Waterproof the foundation from the outside, without hiring a contractor. Dig up the ground around the foundation of your home and coat it with an exterior foundation waterproofing product. There are several types: modified asphalts; rubber; and bentonite clay. Some are designed to last the life of the house when applied in new home construction. Some can be applied with a roller. Check with a building supplies store for the product they recommend.
    • Hire a contractor to build a French drain (drain tile) in your basement, or for less cost, build a baseboard system. To build a French drain, the contractor digs a trench in the basement floor along the walls. A large, perforated pipe is laid in the trench, covered with gravel, to drain the water away. A pit is dug in the floor for the water to drain into, and a sump pump in the pit pumps the water out of the house when the pit fills with water. Once completed, the area is cemented over, except for a 2” gap around the edge of the floor. This gap allows water that leaks into the basement to enter the drain. In a baseboard system, hollow baseboards collect water from weep holes tapped in the bottom row of blocks. The water is channeled to a sump pump in a pit, or to a floor drain.


How to Insulate a Basement Wall by Building an Insulated Stud Wall

Your basement walls will have the greatest insulation if you build a conventional wall next to them and put fiberglass batt insulation in it. This is a do-it-yourself project and there are many good do-it-yourself videos on how to do it. The walls should be finished with drywall or paneling, and this could create a “finished” basement if you mount ceiling panels, lay a waterproof carpet or finish the floor in some other way, and install wiring and electrical outlets in the walls.

  1. Using standard construction methods for interior walls, use 2”x 3” or 2”x 4” boards to build a wall at 1” from the foundation. The thinnest batt insulation is 3½” thick, but this can be used with 2”x3” boards by tearing away 1” of insulation. The 1” gap allows water that leaks in through the foundation wall to fall to the floor. It also allows you to slide plastic sheeting behind the back of the stud wall. bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
  2. Buy 3½” thick Kraft-faced fiberglass insulation rolls or batts at a home center or building supplies store. Buy one roll of polyethylene plastic sheeting at a home center, builder supplies store or paint store. The store should have 20’x 100’ rolls of 6 mil thick polyethylene. Buy ¼” or 5/16” staples to mount the insulation and the plastic sheeting. Buy clear weatherization tape or Tyvek tape to seal the seams in the plastic sheeting. Tyvek tape is available in home centers, where house wrap is sold. bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
  3. Slide the plastic sheeting behind the stud wall, all across each wall. This is a vapor barrier, it protects the insulation from the vapor that passes through the foundation and makes the basement less humid. Stretch it tightly and staple it to the sides of the 2×4’s in a few places. Seal any seams with tape. bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
  4. Hire an electrician to install wiring, switches and electrical outlets. bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
  5. Insert the insulation between the studs with the Kraft paper facing the inside of the house. The Kraft paper is a vapor barrier which protects the insulation from the humidity in the house. At the top, extend the insulation back to cover the sill plate (the board resting on the foundation). Leave a gap between the insulation and the floor to prevent the insulation from absorbing water if water enters through the foundation. Staple the Kraft paper tightly to the studs to create air-tight seals. bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
  6. Mount drywall to the studs. Use either “paper-less drywall”, which has fiberglass in place of paper, or “mold resistant drywall”. This is treated with mold inhibitors. These are both designed to prevent the drywall from becoming moldy if water enters the basement. At least one of these is available at all home centers and building supplies stores. Tape the seams with joint tape and joint compound. Either plaster the wall or mount paneling. Plastering should be done by an experienced person, but an experienced do-it-yourselfer can mount paneling with the help of a do-it-yourself book or website. Paneling should not be mounted without drywall because it would be damaged by the high humidity in the basement. The drywall or paneling should be mounted ½” above the floor to allow for possible water leakage. Mount a baseboard along the wall, also ½” above the floor.


How to Insulate a Basement Wall with Rigid Foam Insulation Covered with Drywall

  1. If your basement walls are exposed block, nail 2”x3” boards or 1”x 3” furring strips to the wall every 16”. Nail them exactly 24” or 16” from center to center so that the insulation can be fitted tightly between. If your foundation is concrete, nail them every 24” to minimize the number of holes. Using 2”x3” boards creates better insulation because you can put in thick, 1” rigid insulation and also have a gap, for dead air insulation. Using 1”x 3” furring strips has the advantage that if there is a door or windows on the wall, less carpentry work is required around them, and the appearance wouldn’t be as bad around them. With 1”x 3” furring strips you should use ½” rigid insulation and have a ¼” gap. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  2. To use 2”x3” boards, cut the boards to a length that allows 2½” above them to leave space to nail one board across the top. This board will trap the air to prevent a convection cycle: air flowing in from the top and out from the bottom or vice versa. Nail the boards into a block wall with 2½” masonry nails, nailed only between the blocks, using a framing hammer or small sledgehammer. Nail boards across the top. Do not nail boards across the bottom because these would trap water that leaks in through the walls. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  3. To use 1”x 3” furring strips, cut the boards to a length that allows 2½” above them, to nail a board across the top. Nail the boards into a block wall with 2” masonry nails, nailed only between the blocks, using a framing hammer or small sledgehammer. Nail a furring strip across the top. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  4. If the walls are bare concrete, apply construction adhesive to minimize the nails used. With construction adhesive you can use two nails per board or furring strip. To apply the construction adhesive, clean off the areas of the walls where the strips will be glued using a wire brush. Coat each strip thoroughly with polyurethane construction adhesive. Hold the strip to the wall and nail it on. If available, use a power activated nailer, with medium power level charges and 2” nails. These use gun powder to drive nails. If one of these is not available, nail the strips with masonry nails using a framing hammer or small sledge hammer. The next day, test if any boards can be pulled from the wall. If the walls were slightly wet in places the adhesion will not be strong there. Remove the boards that you can pull off by hand, use a hair drier to dry the wall and re-glue and re-nail the board. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  5. Buy rigid foam insulation panels with a reflective surface, of a thickness less than that of the boards. There must be a gap next to the reflective surface for it to add insulation value. Also, the gap will create dead air space for better insulation. The R-values of rigid foam insulation panels are printed on the insulation, but this does not include the insulation value of the reflective surface, which depends on the thickness of the space in front of it; the more space the better the insulation. Polyisocyanurate 1” thick rigid foam insulation panels with a reflective surface have an R-value of about R-6, not including the reflective surface. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  6. Using a 48” T-square and utility knife, cut the rigid foam insulation panels into strips to insert between the boards or furring strips. Cut them to fit tightly to prevent air from flowing around them. This will prevent moisture that passes through the foundation wall from damaging the drywall. Cut them to leave a space at the bottom. If the space is cut to be the width of the thickness of the insulation, you can easily hold each insulation panel up off the floor by setting it on a 1”x1” piece of insulation. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  7. If there are windows or a doorway on the wall, you could remove the casing (window frames and door frames) and build out the window or door jambs and window sills. After the drywall is mounted, remount the casing onto it. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  8. Put in the strips of rigid foam insulation. Leave a space below each to allow water to escape if it leaks through the foundation wall. Put a 1”x1” piece of insulation under each panel to prevent it from sliding down. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  9. Mount drywall to the studs. Use either “paper-less drywall”, which has fiberglass in place of paper, or “mold resistant drywall”. This is treated with mold inhibitors. These are both designed to prevent the drywall from becoming moldy if water enters the basement. At least one of these is available at all home centers and building supplies stores. Tape the seams with joint tape and joint compound. Either plaster the wall or mount paneling. Plastering should be done by an experienced person, but an experienced do-it-yourselfer can mount paneling with the help of a do-it-yourself book or website. Paneling should not be mounted without drywall because it would be damaged by the high humidity in the basement. The drywall or paneling should be mounted ½” above the floor to allow for possible water leakage. Mount a baseboard along the wall, also ½” above the floor. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  10. Cut strips of rigid foam insulation and fit them into the space above each wall, against the band joist. Band joists are similar to the other floor joists, but rest on edge on the foundation. They are normally 2”x10” boards. Heat is conducted through them, so they should be covered with insulation.


Insulate Basement Walls with Rigid Foam Insulation Not Covered by Drywall

  1. To insulate the walls and not cover them with drywall or paneling, glue foil-faced 4’x8’ sheets of rigid foam insulation to the walls. Most brands of rigid foam insulation cannot be used because they emit noxious fumes in a fire. These have warnings on their labels such as “This product should be separated from the building interior by a thermal barrier, usually ½” gypsum board”. Gypsum board is normally called drywall. If you don’t use foil faced insulation you can paint the tape and the insulation. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  2. Nail 1”x3” furring strips to the wall every 24”. Mount them accurately so that the edges of insulation panels extend to the exact centers of furring strips. Use 2” masonry nails. If your foundation is block, nail only between the blocks. If your foundation is concrete, apply polyurethane construction adhesive to the furring strips so you will only need to use two nails for each, and use a power activated nailer if available, with medium power level charges and 2” nails. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  3. Mount the first row of 4’x8’ insulation panels horizontally along the walls, over top of the furring strips. Cut the insulation using a T-square and utility knife. If the panels are foil faced, their foil side should face the inside of the house to reflect heat. Nail on the panels with roofing nails. Leave a ½ “gap below them to allow water to drain out if it leaks through the foundation walls. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  4. Cut and mount the second row of panels. Seal the seams with TyvekTM tape to block moisture from entering the house. This is available in home centers, where house wrap is sold. You can paint the panels if they not foil faced.


How to Fill Empty Walls with Loose Fill Cellulose Insulation

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Before You Begin:

  1. Decide whether it would be easier to fill the walls from the inside or the outside of the house. If you have siding in horizontal strips (lap siding), it may be easier to fill the walls from the outside, by removing one or two strips on each wall. Blowing in the insulation from the outside would then be a do-it-yourself project. Filling the walls from the inside would probably require that you hire someone to repair the many 2” or 3” holes in the wall, and you would also need to re-paint the walls. If you have brick or stucco walls you must blow in the insulation from the inside. bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
  2. In some very old homes, loose fill insulation can be poured into the walls from the attic because the spaces between the wall studs are open at the top. If your home is very old, check if your walls are open at the top. bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
  3. Some old homes have fiberglass insulation that is only about 1” thick. The walls can be filled using an insulation blower, but it is more difficult than if the walls were empty, and may not be worth the time and expense if your climate is not cold. If you rent a blower from an insulation company, they may be able to advise you on how to do this. bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
  4. If your home has very old wiring, hire a qualified electrician to inspect the wiring in the exterior walls before installing insulation. An electrician can inspect it by looking into the electrical boxes at the switches and outlets on the exterior walls. In many old homes, some circuits have the original wiring and other circuits have more modern wiring, so if you see modern wiring in the basement, you can’t assume that all of the wiring is modern. You can check if some of your home’s circuits have very old wiring by checking the cables as they enter the main electric panel. If they all are covered with plastic insulation (Romex wiring), you have no very old cables. Older electric cables are covered with different types of insulation. bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
  5. If any walls show evidence of water leaks, have the leaks repaired before installing insulation. New insulation could absorb water and remain wet for a long time, causing damage to the walls. bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
  6. Rent an insulation blower and buy the insulation. Ask the salesperson for advice on how to use the blower. Buy plastic plugs to repair the holes in the sheathing if you will blow in the insulation from the outside. These are not sold everywhere that blowers are rented. Insulation blowers can be rented at home centers, rental centers, builder supplies stores, and some insulation supply companies. An insulation supply company would probably offer you the best advice on using them. Also, you may need to go there to buy plastic plugs. See, “Fill the Walls from the Outside of the House”, directly below. Ask to borrow a 12-amp extension cord if you don’t own one. bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
  7. Hoses 50’ and 75’ long should be available. Use a 50’ hose if this is long enough because insulation will flow through it more easily.


Fill the Walls from Outside the House

  1. Remove one row of siding at the top of each floor. If you have aluminum siding, you need to watch a video in a do-it-yourself website. After removing a piece of aluminum siding, cut the house wrap or other vapor barrier where you will drill holes, and peel it down to be stapled up later. If you have wood or fiber cement lap siding, first cut the caulk that bonds the siding board at its ends. Then, pry up the piece ¼” to ½” with a stiff, wide-blade putty knife and tap it back into place. The head of a nail should then stick out slightly and the nail can be pulled out. There should be one nail every 16”. Cut the house wrap or other vapor barrier where you will drill holes, and peel it down to be stapled up later. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  2. After removing the row of siding, drill 2” or 3” holes, depending on the size of the hose, into the sheathing at 16” intervals, midway between each pair of wall studs. The nails in the sheathing will show the stud locations. At each hole, drop a plumb bob or any weight on a string to check if the cavity extends to the bottom of the floor. There may be a board about half-way up the wall, which is a fire stop. If so, remove a row of siding directly below it, and drill a hole every 16” as at the top of the wall. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  3. To blow in the insulation, carefully read the instructions given with the blower. Mount the ladder firmly and be very careful as you climb it. Be careful not to trip on the hose. Insert the blower hose to the bottom of the cavity and then turn on the blower. Slowly pull out the hose while filling the cavity with insulation. When the space is filled, insulation will blow out from the hole. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  4. Plug the hole in the sheathing with plastic plugs if you have them. They are sold by some insulation companies. If not available, cut a ¼” plywood panel into 6”x6” pieces and glue a piece over each hole with construction adhesive. Use an adhesive labeled to be for “indoor/outdoor use” and with a “high tack”. An adhesive’s tack is a measure of how well the objects stick together when first joined. If the tack is high and you use ¼” plywood the panel will stick immediately so you won’t need to nail it. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  5. Put the building paper back in place and staple it or nail it with ¾” roofing nails, and then tape it where it was cut using Tyvek tape. Replace the siding. If the siding is wood or fiber cement lap siding, nail it on using the original nail holes to prevent water from entering the holes. It would be better to use ½” longer nails. If you use new nails, use ring-shank siding nails or spiral galvanized nails. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  6. If the siding is wood or fiber cement lap siding, carefully caulk  the gaps at the ends of the piece of siding with a brand of silicone sealant for outdoor use. Silicone sealant has excellent elasticity.


Fill the Walls from Inside the House

  1. Move the blower to a location outside the house, next to the wall you will insulate, and extend the hose into the house through a window. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  2. Locate the wall studs. Use a stud finder or knock on the walls to find the approximate location of each wall stud. The wall will feel solid at every wall stud, which will be spaced 16” apart. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn

    Hole saw bit

    Hole saw bit

  3. Use a hole saw bit to drill a hole between every two wall studs at the top of the wall, of the blower hose diameter, which will be 2” or 3”. Leave a space of several inches above it to allow for plaster repair. Drill in only to the depth of the wall material to avoid cutting a cable. The walls will be made from ½” thick drywall, unless the home was built before the 1960’s. These very old homes had plaster walls which were made of plaster on wood strips, and were thicker than ½”. Always check by drilling in exactly ½” because the original wall may have been replaced with a drywall wall. Drop a plumb bob or any weight on a string into each cavity to check if it extends to the bottom of the floor. Do this for every hole. There may be a board about half-way up  the wall, which is a fire stop. If so, drill a hole directly below it. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  4. To blow in the insulation, carefully read the instructions given with the blower. Insert the blower hose to the bottom of the cavity and then turn on the blower. Slowly pull out the hose while filling the cavity with insulation. When the space is filled, insulation will blow out from the hole. nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
  5. Hire an experienced person to repair the holes. Experienced house painters are normally qualified.

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Types of Siding Available

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These types of siding are currently sold, older homes may have other types of siding. Some siding boards and shingles are available in real wood, engineered wood, and fiber cement.

Engineered Wood Siding

Engineered wood siding, which is made from “engineered wood”, also called composite siding, is manufactured by binding strands, particles or fibers of wood with glue. The materials used are treated with chemicals that make them rot-resistant, but this type of siding does always not last as long as real wood. The maximum warranty available may be 30 years, and some warranties are only 20 years. Their life is hard to predict, especially for brands that have not been on the market long. They require similar maintenance to wood siding, to be painted every 5-10 years.

It has advantages over wood siding:

    • Less costly
    • Pre-primed so it can be installed without painting
    • Available in longer pieces (16 ft.), so there will be fewer seams

Its main disadvantage real wood siding is that it wood siding will eventually need to be replaced.

Fiber Cement Siding

Fiber cement is a mix of wood pulp and Portland cement. It is fire-proof, rot-proof, and termite-proof. It is now on 15% of new homes. It is available in pieces resembling the most popular styles of wood siding; clapboard, shiplap, shingles, etc. The pieces are nailed on like wood siding and can be cut like wood. It looks just like wood but costs much less. Installing it is not a do-it-yourself project because it is very hard to install.

It is not available as insulated siding with foam fused to the back, so using it will only increase the R-value of your walls if you mount it over insulation sheathing. In fact, the R-value of the material alone may be only about R-0.15.

Fiber cement siding that absorbed water

Fiber cement siding that absorbed water

Fiber cement siding has several problems:

    • It is the most difficult type of siding to install properly and many installers are poorly-trained and install it poorly.
    • Its worst problem is that it can absorb water and swell up if it is in a very wet location on the wall. It is made with cellulose, which is sawdust or wood pulp. Most houses have spots where much water flows down the siding, and this can cause the cellulose to expand.
    • In areas on the walls where the siding gets very wet, if fiber cement siding absorbs even a small amount of water, the paint can peel.

Board and Batten Siding

Board-and Batten Siding

Board-and Batten Siding

Board and batten siding is made from wide vertical boards of real wood, with thin strips of wood, called “battens” covering the seams where the boards join. It is available in several species of wood, including cedar, redwood and pine, but some species are only available in certain regions on the country. This type of siding can be very attractive.

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Shiplap and Clapboard Siding

Clapboard siding

Clapboard Siding

Shiplap Siding

Shiplap Siding

Shiplap siding is made of horizontally-mounted boards, which overlap each other with the top of one board fitting into a notch (rabbet) in the bottom of the board above it. The boards can be made real wood or engineered wood or fiber cement.

Clapboard siding is made of horizontally-mounted boards that are thinner on the top. Each board overlaps the board below it. It has a higher R-value than shiplap siding because there is a space behind each board which is dead air insulation.

Shiplap and clapboard siding  are called “lap siding”. There are other, uncommon types of lap siding. The most common types of wood used for shiplap and clapboard siding are pine, white fir, cedar and redwood. Pine and white fir are not rot-resistant so they must be painted or stained regularly. Cedar and redwood have a natural resistance to decay, but they should be coated periodically with a wood preservative or wood stain.  Applying wood preservative or wood stain is much easier than painting, and is a do-it-yourself project.

Lap siding can be installed by experienced do-it-yourselfers, but it takes much more time than installing vinyl or aluminum siding.

Plywood Siding

Plywood siding

Plywood siding

Wall Covered by Plywood Siding

Wall Covered by Plywood Siding

Plywood siding is a low-cost alternative to other types of siding, and is also the quickest and easiest to install. It has acceptable durability in dry climates. It is installed as 4’ x 8’ panels with grooves to give the appearance of vertical boards. It can last up to 30 years if properly maintained, but it often rots at the bottom because the homeowners didn’t adequately paint the bottom edge, allowing water to “wick” in.

Vinyl Siding

Vinyl siding is the most popular type of siding for covering existing siding. It competes mainly with aluminum siding. They are both relatively inexpensive, easy to install and require little maintenance. Vinyl requires less maintenance than aluminum, but it should probably be washed periodically. It becomes brittle in cold weather, so it can be damaged more easily when the weather is cold. For this reason it isn’t normally used where the climate is very cold. It is probably the easiest siding for do-it-yourselfers to install.

Vinyl siding doesn’t have some of the problems associated with aluminum siding: the paint scratching off, denting, and being noisy when wind blows. It is growing in popularity, partly because it has attractive styles which imitate the look of wood siding. It is made of PVC, with the coloring in it. As a result, scratches are not noticeable and it doesn’t need painting. It has the problem that it can break, but the heavier brands are fairly strong, they can withstand stones thrown by lawnmowers.

Its problems are that it has a small tendency to crack and split, and it can look faded and dingy after not too many years. Some homeowners paint it, but this is not recommended. Manufacturers have made some improvements on these problems.

There is a common belief that vinyl siding insulates better than aluminum siding because aluminum conducts heat faster. In fact, it insulates only very slightly better than aluminum because most of the resistance to heat flowing through any type of siding is created at the siding’s inner and outer surfaces. The outer surface resists solar radiation (UV radiation) and the inner surface resists heat radiation (infrared radiation). Also, the air behind the insulation is “dead air insulation” even though it would be more effective if it couldn’t flow out.

Insulated vinyl siding is bonded with StyrofoamTM   or another brand of foam. It insulates well if the foam is thick. Also, this makes it much stronger against impacts because the insulation fills out the profile. This extra strength also prevents it from becoming slightly “wavy”, which can happen to vinyl siding. Some of its manufacturers claim that it allows vapor to pass through it from the inside better than other insulation products. Allowing vapor to escape prevents mold from growing in the walls. Ask the contractor who would install it if their product is “breathable”.

Dutch lap insulated vinyl siding

Dutch lap insulated vinyl siding

Clapboard insulated vinyl siding

Clapboard insulated vinyl siding

 

 

 

 

 

 

 

 

 

 

Aluminum Siding

4" aluminum siding with wood grain finish

4″ aluminum siding with wood grain finish

Aluminum siding is the second most popular type of siding for covering existing siding. It has these advantages over the other types of siding:

    • easiest to install, so there is less risk of poor installation
    • most durable.
    • can be used in very cold climates, where vinyl siding is prone to crack
    • unlike vinyl siding, it is normally fade resistant, but some painted finishes can fade or allow chalk to run onto brick walls below it.
    • like vinyl and steel siding but not the other types, it is available with thick foam insulation bonded to the back of it.
    • available in a wide variety of colors and finishes, including wood grain finish.
    • has several disadvantages, which together have made it less popular than vinyl siding:
    • paint can scratch off, but newer, more expensive vinyl-coated finishes are more scratch-resistant.
    • prone to denting
    • can be noisy when the wind blows
    • lacks the ability for detailed trim work.
    • prevents a Wi-Fi signal from passing through, so members of the household cannot use laptop computer or other portable device on the porch or patio. It causes no problem with the Wi-Fi signal inside the house.

Insulated aluminum siding is bonded with StyrofoamTM   or another brand of foam. This increases the R-value significantly if the foam is thick, but some brands have a thin sheet of foam.

Steel Siding

Steel siding has several advantages over vinyl and aluminum siding:

    • May have the best long-term value
    • Not prone to denting
    • Superior protection against high winds and hail

It has many disadvantages:

    • Not available in as many styles and colors as vinyl and aluminum
    • When it gets scratched you should paint the scratch immediately to prevent rust.
    • Itis difficult to handle and cut, so installing it is not a do-it-yourself project. To install it you must find a contractor who is experienced with steel siding, not aluminum siding.
    • Insulated steel siding may not be available, but you can install steel siding it over insulation sheathing. See below Insulation Sheathing: Panels and Fanfold Underlayment
    • Lacks the ability for detailed trim work.

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Insulated siding
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“Insulated siding” is common siding of any type mounted over insulation sheathing.  The sheathing is commonly a foam sheet that covers the walls under the siding. It is a relatively new way to add insulation value to walls. It insulates by reducing heat conduction, and if the siding is not designed to be air-tight, the insulation sheathing will stop air from leaking through the walls. Some has a reflective surface, which adds insulation value by reflecting heat radiation (infrared radiation).

Before insulation sheathing was used, the wood sheathing that covered the walls was covered with tar paper or felt paper as a vapor barrier, and the siding was mounted directly to it. If your home is old, this is probably how your walls are constructed. Tar paper vapor barriers in old houses were not taped at the seams, they simply overlapped, so air can leak through. The seams are always taped when insulation sheathing is mounted. Also, since heat energy is conducted through wall studs and insulation sheathing covers the wall studs, this further reduces the heat flow through the walls.

Fanfold Underlayment

Fanfold Underlayment

If you are mounting siding over existing siding, first cover the existing siding with insulation sheathing called “fanfold underlayment”. This is sold in 4 ft. by 50 ft. pieces that fold up like a fan. It is the only type of thin insulation sheathing.  You only need to apply tape to the top and bottom seams, not the panels’ sides. Seal the seams above and below each sheet with Tyvek™ tape. Fanfold underlayment is available in thicknesses of ¼” and 3/8”, with and without  a reflective surface on one side. A reflective surface only adds insulation value if there is a space next to the reflective surface.

Insulation sheathing is made from several types of rigid foam, each with different R-values. The R-values are printed on the panels. The material is usually not printed on the panel. The panels made of blue, green or pink rigid foam are made of extruded expanded polystyrene, which is Styrofoam ™. It has a relatively low R-value and is less expensive. Its R-value is R-5 for a 1”thick panel and R-3 for a ½” panel. Polyisocyanurate has a higher R-value and is more expensive. A 1”thick panel has an R-value in the range of R-6 to R-7. Panels made of polyisocyanurate have one reflective surface on each panel, so add the R-values created by the reflective surfaces, which is very roughly R-2. The insulation value added by a reflective surface will be greater in very hot or very cold climates, and greater if the space next to it is greater.

Any 4’x 8’ rigid foam insulation panels from ½” to 1” thick can be used as insulation sheathing if you are replacing the siding, but these panels are too thick to fit between old siding and new siding. Fanfold underlayment must be used. The R-values printed on the panels can only be used to compare the panels, the increase in the R-value of your walls depends on several factors. The panels will increase the R-value of your walls by much less than the value printed on them, and it is hard to estimate what it will be. If your siding is not designed to trap air behind it, insulation sheathing will be much more effective because it will trap air to create dead air insulation.

Panels with a foil-faced reflective surface are impermeable, that is, vapor cannot pass through them. Panels with no facing of any material are semi-permeable. Panels labeled as “vapor retarder” have a facing that is not a foil-faced reflective surface. They are less permeable than panels with no facing. If you want insulation sheathing that has a relatively high R-value and is not impermeable, i.e., it allows no vapor to pass through, you may have to buy it at an insulation supply company. Your local home center will probably only carry one type of high R-value insulation sheathing and it has a reflective surface.

To create the highest R-value, mount the panels tightly together and tape the seams. Some panels have “shiplap edges” which create tighter seals. If you have hired a contractor to mount the insulation sheathing, check that he is taping the seams and fitting the edges tightly together. If you will install it yourself, obtain instructions from the manufacturer. You should also check your local building and fire codes.


How Much Could Insulation Sheathing Lower Your Heating and Cooling Costs?

If you mount insulation sheathing when replacing your siding, there are situations where it would probably be a good investment. If you mount the insulation sheathing yourself and save the cost of labor, it is likely to be a good investment. If it is very cold where you live, and especially cold and windy, insulation sheathing is likely to be a good investment.

A DOE study done in 2004 at the Oak Ridge National Laboratory titled, “Retrofit Best Practices Guide: How to Save Energy When You Fix up the Outside of Your Not-So-New House” estimated a homeowner’s potential savings in heating and cooling costs if they remove siding that has no insulation sheathing and replace it using insulation sheathing. The study compares two types of rigid foam, at different thicknesses, with and without foil facing. The results can be better understood by knowing that polystyrene is R-5 per inch of thickness and polyurethane is about R-6.5 per inch of thickness. The study estimated the range of potential savings in ten cities. The results are given below for two of those cities, Chicago and Atlanta. Single-story homes are more likely to be near the bottom of the ranges.

Potential Annual Heating and Cooling Energy Savings for Different Wall Retrofit Options in Chicago
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Potential Annual Heating and Cooling Energy Savings for Different Wall Retrofit Options in Atlanta
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If you are handy enough to attempt DIY wall insulation you can make many small and large improvements to your home that should greatly lower your utility bills.

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